ATLANTA — David Krejci scored a goal and assisted on another, Tuukka Rask blanked Atlanta for the second time this season, and the Bruins kept up their mastery of the Thrashers with a crucial 4-0 victory Tuesday night that extended Boston's lead for the final playoff spot in the Eastern Conference.

The Bruins moved three points ahead of the Thrashers in the playoff race.

Krejci put the Bruins ahead less than 10 minutes into the opening period, then set up Milan Lucic's goal that made it 2-0. Miroslav Satan scored off a deflection with just four seconds left in the second, and Steve Begin put it out of reach with a goal early in the third.

Rask stopped a penalty shot and made 28 saves in all to beat Atlanta for the third time this season, including a pair of 4-0 victories. The Bruins have won 10 in a row over the Thrashers, whose last win against Boston came on Dec. 29, 2007.

Despite trading Ilya Kovalchuk just before the Olympic break, Atlanta had outscored opponents 18-9 during its recent four-game winning streak, which improbably moved the Thrashers back into the thick of the playoff race.

But the Thrashers had no answer for Rask, who has won all three of his starts against Atlanta with a 0.97 goals-against average.

His biggest save came on Colby Armstrong, who had scored four goals in Atlanta's last four games. Going in on a breakaway with the Thrashers trailing 2-0, the winger was hooked from behind by Dennis Wideman and awarded a penalty shot. But Armstrong failed to convert, his attempt at the upper right corner turned away by Rusk's quick glove.

The Bruins went ahead at 9:25 of the opening period thanks to good work along the boards by Krejci. He worked the puck behind the Atlanta net before sliding it back to Michael Ryder, who popped out in front to lure away the defense in front of goalie Johan Hedberg. Krejci slipped out on the other side, took a return pass from Ryder and stuffed the puck past a helpless Hedberg.

Krejci set up Boston's next goal at 7:59 of the second. Lucic circled alone in front of the net, took a pass from his teammate and ripped a shot over Hedberg's glove hand to double the lead.

The real killer for the Thrashers came just before the end of the period. Patrice Bergeron won a faceoff, sliding the puck back to Zdeno Chara just inside the blue line. The big defenseman fired it toward the net, where Satan deflected it past Hedberg with four seconds remaining before the second intermission.

Any thoughts of an improbable comeback were quickly snuffed out by Begin's fourth goal of the season, less than two minutes into the third. Some fans began heading to the exits while the Bruins celebrated their four-goal cushion.

Notes The Thrashers have been shut out four times this season. … Boston C Vladimir Sobotka went out in the first period with an undisclosed injury and didn't return. … Atlanta tough man Eric Boulton duked it out with Shawn Thornton and tried to lure Begin into a fight late in the game. The linesmen stepped in, and Boulton alone went to the box for cross-checking.